Display error code for U2F errors

See merge request !7305

Apply margin on alert banners only when there is one or more alerts

## What does this MR do?

Fixes extra margin added to all pages by !8151

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

## Screenshots (if relevant)

![screenshot](https://gitlab.com/gitlab-org/gitlab-ce/uploads/f8804454e82a61246d10fa026605fbb3/Screen_Shot_2016-12-19_at_2.04.42_PM.png)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #25835

See merge request !8209

Rename SlackNotificationService back to SlackService

## What does this MR do?

See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/8191#note_20310845

## What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/25843

/cc @yorickpeterse @stanhu @smcgivern @felipe_artur @ayufan

See merge request !8208

Resolve "Direct link from pipeline list to builds"

## What does this MR do?
- Adds a dropdown with builds in the mini pipeline graph in the pipelines table
- Unnest a lot of CSS related with pipelines in order to make it reusable

## Screenshots
![Screen_Shot_2016-12-15_at_14.45.41](/uploads/ca1c61842a422a34383e029d668034b7/Screen_Shot_2016-12-15_at_14.45.41.png)
![Screen_Shot_2016-12-15_at_14.45.49](/uploads/952e3277143639ce4ad111103034faeb/Screen_Shot_2016-12-15_at_14.45.49.png)
![Screen_Shot_2016-12-15_at_14.46.02](/uploads/f7369a124b1c3c0db4194de2cb637ef0/Screen_Shot_2016-12-15_at_14.46.02.png)

![graph_animation](/uploads/9bae036cb5acff499f992a4722943d72/graph_animation.gif)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
Closes #25071 
Closes  #19703 

See merge request !8097

Fix N+1 queries on milestone show pages

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/25832

See merge request !8185

Rename "Online terminal" to "Web terminal" in the documentation

## What does this MR do?

Renames online terminals to web terminals in some recently merged documentation

## Are there points in the code the reviewer needs to double check?

I think I've caught all the links

## Why was this MR needed?

We're calling it 'web terminal' in the release post, and consistency is ✨ 

https://gitlab.com/gitlab-com/www-gitlab-com/merge_requests/4007/diffs#note_20283597

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !8190

Fix sizing of avatar circles; add border

* Adds border to group and project avatars
* Fixes cut-off circles
![Screen_Shot_2016-12-20_at_8.25.12_AM](/uploads/24e0eedf001f230300a316c504af59d4/Screen_Shot_2016-12-20_at_8.25.12_AM.png)
![Screen_Shot_2016-12-20_at_8.24.59_AM](/uploads/23450bf1f99b8075a043dd5512185e91/Screen_Shot_2016-12-20_at_8.24.59_AM.png)
Closes #25733

See merge request !8194

Allow unauthenticated access to Repositories Files API GET endpoints

See merge request !8149

Use gitlab-workhorse 1.2.1

More prometheus metrics, other small fixes.

See merge request !8197

hides new issue btn for not loggedin user

## What does this MR do?
This MR closes #25093 #25180
## Are there points in the code the reviewer needs to double check?
NR
## Why was this MR needed?
Prevent issue creation for no logged in user and some confusion related to 
## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- Tests
  - [ ] All builds are passing
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
Closes #25093, #25180

See merge request !8175

Make 'unmarked as Work In Progress' system note more consistent

See merge request !8193

Memoize Milestoneish#issues_visible_to_user to reduce lookups

https://gitlab.com/gitlab-org/gitlab-ce/issues/25748

See merge request !8146

Signed-off-by: Rémy Coutable <remy@rymai.me>

Signed-off-by: Rémy Coutable <remy@rymai.me>

Allow Repositories API GET endpoints to be requested anonymously

Closes #4269

See merge request !8148

Changes after review

Smarter refreshing of authorized projects

This MR reworks the way `User#refresh_authorized_projects`, resulting in a much more efficient process leading to fewer dead tuples.

Related issue: https://gitlab.com/gitlab-org/gitlab-ce/issues/25257

See merge request !7956

Remove unnecessary method `build_user` from model `User` 

Closes #25678

See merge request !8162

Fix member with expiration date feature spec

See merge request !8186

Memoize Milestoneish#issues_visible_to_user and counts to reduce lookups
Milstoneish SQL optimised with project, but still slow on GlobalMilestone

Signed-off-by: Rémy Coutable <remy@rymai.me>

Move admin projects spinach tests to RSpec

Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/23036

See merge request !8174

Add doc for pipeline duration

The description was copied and modified from !6084

See merge request !6445

Add doc for the Gitea importer

This adds documentation for !8116. It's mostly a copy/paste of the GitHub import documentation without the OAuth parts since Gitea is not yet an OAuth provider.

Part of #22348.

See merge request !8139